By Kim Bo-eunThe United Nations Command (UNC) for the first time disapproved plans for an inter-Korean railway inspection, amid a deadlock in denuclearization talks between North Korea and the U.S.The plan was for a South Korean train to travel up to the North's northwestern city of Sinuiju so officials of the Koreas could inspect the condition of the tracks in the North from Aug. 22 to 27.The UNC holds authority to approve personnel and supplies crossing the Military Demarcation Line (MDL).The government has stated the inspections do not go against sanctions imposed on the North by the U.N. and the U.S.The UNC initially cited the reason for disapproval as South Korea not notifying it of its plan 48 hours in advance.A unification ministry official said this was likely not the issue."There were many instances in which plans that were announced less than 48 hours in advance were approved," he told reporters, Thursday.The UNC, in an official statement, said it "required South Korea to submit details of the planned visit." Calling for additional details is seen as unprecedented.Cheong Wa Dae spokesman Kim Eui-kyeom said South Korea is "closely consulting with the U.S." on the matter.Views are that the U.S. is attempting to curb inter-Korean exchanges while North Korea is holding out on making progress on denuclearization.The chief of the UNC is also the commander of the U.S. Forces Korea.The disapproval of the railway inspection plan comes shortly after U.S. Secretary of State Mike Pompeo's visit to Pyongyang was canceled, citing lack of progress in North Korea's denuclearization.Other inter-Korean projects such as opening a joint liaison office in the North's city of Gaeseong have also been put on hold.The U.S. stance on inter-Korean affairs has been that it should go together with North Korea's denuclearization.Pyongyang has not taken any concrete denuclearization steps since its leader Kim Jong-un's summit with U.S. President Donald Trump in June. There were expectations that North Korea could agree to submit a list of its nuclear weapons in a high-level meeting with Pompeo, but no progress was made as the meeting fell through. The inter-Korean railway project is among the agreements in the Panmunjeom Declaration reached between President Moon Jae-in and North Korean leader Kim Jong-un in April. The Koreas have been engaging in preparations to modernize and connect the two countries' rail networks, but these have been limited to inspections as sanctions bar them from taking things further. South Korea has stated plans for work on the project will begin within the year, amid expectations the North would take denuclearization measures.